1. Technical Field
The present invention relates in general to hard disk drives and, in particular, to an improved system, method, and apparatus for an integrated bypass channel and diverter that is especially useful for hard disk drives having a small form factor
2. Description of the Related Art
Data access and storage systems generally comprise one or more storage devices that store data on magnetic or optical storage media. For example, a magnetic storage device is known as a direct access storage device (DASD) or a hard disk drive (HDD) and includes one or more disks and a disk controller to manage local operations concerning the disks. The hard disks themselves are usually made of aluminum alloy, glass or a mixture of glass and ceramic, and are covered with a magnetic coating that contains the bit pattern. Typically, one to five disks are stacked vertically on a common spindle that is turned by a disk drive motor at thousands of revolutions per minute (rpm). Hard disk drives have several different typical standard sizes or formats, including server, desktop, mobile and micro drives.
A typical HDD also uses an actuator assembly to move magnetic read/write heads to the desired location on the rotating disk so as to write information to or read data from that location. Within most HDDs, the magnetic read/write head is mounted on a slider. A slider generally serves to mechanically support the head and any electrical connections between the head and the rest of the disk drive system. The slider is aerodynamically shaped to glide over moving air in order to maintain a uniform distance from the surface of the rotating disk, thereby preventing the head from undesirably contacting the disk.
A slider is typically formed with an aerodynamic pattern of protrusions on its air bearing surface (ABS) that enables the slider to fly at a constant height close to the disk during operation of the disk drive. A slider is associated with each side of each disk and flies just over the disk's surface. Each slider is mounted on a suspension to form a head gimbal assembly (HGA). The HGA is then attached to a semi-rigid actuator arm that supports the entire head flying unit. Several semi-rigid arms may be combined to form a single movable unit having either a linear bearing or a rotary pivotal bearing system.
The head and arm assembly is linearly or pivotally moved utilizing a magnet/coil structure that is often called a voice coil motor (VCM). The stator of a VCM is mounted to a base plate or casting on which the spindle is also mounted. The base casting with its spindle, actuator VCM, and internal filtration system is then enclosed with a cover and seal assembly to ensure that no contaminants can enter and adversely affect the reliability of the slider flying over the disk. When current is fed to the motor, the VCM develops force or torque that is substantially proportional to the applied current. The arm acceleration is therefore substantially proportional to the magnitude of the current. As the read/write head approaches a desired track, a reverse polarity signal is applied to the actuator, causing the signal to act as a brake, and ideally causing the read/write head to stop and settle directly over the desired track.
The motor used to rotate the disk is typically a brushless DC motor. The disk is mounted and clamped to a hub of the motor. The hub provides a disk mounting surface and a means to attach an additional part or parts to clamp the disk to the hub. In most typical motor configurations of HDDs, the rotating part of the motor is attached to or is an integral part of the hub. The rotor includes a ring-shaped magnet with alternating north/south poles arranged radially and a ferrous metal backing. The magnet interacts with the motor's stator by means of magnetic forces. Magnetic fields and resulting magnetic forces are induced via the electric current in the coiled wire of the motor stator. The ferrous metal backing of the rotor acts as a magnetic return path. For smooth and proper operation of the motor, the rotor magnet magnetic pole pattern should not be substantially altered after it is magnetically charged during the motor's manufacturing process.
Hard disk drives with small form factors can present particularly challenging design constrains due to their lack of space or “real estate” within the drive enclosure. For example, designing a diverter for an aerodynamic bypass channel with the drive can have several geometric constraints from an assembly standpoint. As shown in FIG. 1, conventional drives having small form factors have no supporting platform in the vicinity 11 of the bypass channel 13. This presents a problem during the installation process where the bypass and/or diverter 13 would have an unsupported overhang 15 that encroaches into the VCM area 17. As shown in FIG. 2, this encroachment of the overhang 15 can persist even in the installed position. There also is a lack of space for the datum planes (e.g., walls) that are needed to slidingly align the bypass/diverter into its proper position during installation. Thus, an improved system, method, and apparatus for a bypass channel and diverter for hard disk drives having small form factors would be desirable.